In 1977, Ilić started publishing his works in the established comics magazines outside Yugoslavia, such as Alter Alter, Métal Hurlant, Heavy Metal and Marvel's Epic Illustrated. In 1980, Novi kvadrat ceased to exist and Ilić entirely stopped working on the comics, and focused upon illustration and graphic design. In 1982, he started working for the Italian magazine Panorama.

He stopped working for the magazines in 1985, and in March 1986 he left Yugoslavia and went to New York "with $1,500 in the pocket and no idea what to do upon getting there". Yet, he soon started publishing his illustrations in Time, New York Times, Wall Street Journal, and many other prominent and influential newspapers and magazines. In 1991, he becomes an art director of Time International, and the following year he became art director of the op-eds in the New York Times.

In 1993, Ilić became one of the co-founders of Oko & Mano Inc. graphic design studio, and in 1995 he founded Mirko Ilić Corp., a graphic design and 3-D computer graphics and motion picture title studio. In 1998, he created the title sequence for the romantic comedy You've Got Mail with Milton Glaser and Walter Bernard.

In 2015, 38 pieces of his artwork were included in the permanent collection of the Museum of Modern Art (MoMA). MoMA acquired artwork including posters, LP designs from his Yugoslavian period. In September 2015, four of his pieces were exhibited for the first time in MoMA's exhibition Making Music Modern.